Volume of signing isn't totally unrelated - even if you presume 4 hours of signing time per day, most people don't speak/sign for that long an amount of time. I

Volume of signing isn't totally unrelated - even if you presume 4 hours of signing time per day, most people don't speak/sign for that long an amount of time. It's more than a typical deaf person, any way you slice it. But, you're right - the manner of signing has something to do with it as well, and I've amended my comment to reflect that. :)